Design of noise barriers for the mitigation of construction noise

Noise pollution is a major problem in many major cities in particular a small island state like Singapore with residential buildings very close to the major trunk roads and expressways. The problem is aggravated by the ongoing city redevelopment and construction of new mass rapid transit lines. Construction noise is therefore a common theme of public complaints and therefore there is an increased interest in the development of more effective mitigation measure for construction noise. In this work, a Flat-tip jagged-edge profile was investigated and applied on the edge of a cantilever (slanted up for 45 degrees, facing the noise source) which was mounted at the top of a passive noise barrier. Besides the numerical simulations, the full sized prototypes were also experimentally tested on a construction sites with noise generated by a boring machine. Both numerical simulations and experimental results showed that this barrier with a slanted Flat-tip jagged cantilever would perform better than the traditional barrier having a Straight-edge cantilever of same height, with a maximum additional attenuation of 5.0 dBA experimentally obtained. The barrier with slanted Flat-tip jagged cantilever could also extend the shadow zone behind the barrier to higher levels of the building.